PhD Thesis FOOD WEB SIMULATION STUDIES ON AQUATIC ECOSYSTEMS


Abstract

There is an increasing interest in dynamical food web modeling, and recent advances of computational biology provide new algorithms and tools for modern systems ecology. In this work stochastic individual- based models are used for simulating food web dynamics in two case studies: the Kelian river, in Borneo, Indonesia and a marine ecosys- tem in Gulf of Guinea. The two cases present e ects from human perturbations. In both cases, we constructed food webs, based on real databases. We parameterized the stochastic dynamical model for the system models and performed sensitivity analysis (and community re- sponse indicators) in order to quantify the relative importance of sys- tem components. The main aims are to understand the importance of functional diversity of aquatic ecosystems and relations between the dynamics of species and the whole community in perturbed ecosys- tems due to human activities (pollution due to gold mining activity and human settlements in the case of the Kelian river ecosystem and the impact of Fish Aggregation Devices on skipjack tuna communi- ties in the case of the Gulf of Guinea ecosystem). In Kelian river case, our results suggest that invertebrate shredders are indicators of hu- man impact on the river. In downstream sites our results show that the river is more polluted and the relative importance of grazers and shredders decrease. The primary producers disappear downstream as consequence of mine activity and human waste. In the marine system case study, we analyzed the e ects of association between tunas and FADs, and compared this to the behavior of free tuna individuals. The results suggest that skipjack tuna is a ected by the use of FADs as shing strategy on them. Some individual species show more sensibility to variation of population size of tuna. These two studies contribute to better understand how functional di- versity is related to human impact. This kind of approach may help in shaping systems-based conservation and marine sheries management strategies.



Paper Details

Authors

N. Gjata

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Language

English
.